A variety of diseases can affect bone tissue resulting in lesions and tumors of the bone. Primary bone tumors, either benign or malignant, may originate in cartilage cells, osteoblastic (osteoid- or bone-forming) cells, fibroblastic cells, primitive mesenchymal cells, and hematopoietic cells, as well as nerve and vascular tissue, notocordal remnants, and other sites. Benign tumors of the bone include enchondroma, osteochondroma, osteoid osteoma and osteoblastoma, giant cell tumor (also malignant), chondroblastoma. Malignant tumors include multiple myeloma, metastatic carcinoma central chondrosarcoma, osteogenic sarcoma, osteogenic sarcoma medullary fibrosarcoma peripheral chondrosarcoma and Ewing's sarcoma.
The most common forms of malignant bone tumor are attributable to metastatic disease. In fact, bone is the third most common site of metastatic disease. Treatments for bone metastases are limited in nature and generally only palliative.
Pain is one of the more prevalent and debilitating complications of bone tumors and lesions. Approximately 40% of patients with cancer develop metastatic disease; of these patients, 50% have poorly controlled pain. Unfortunately, achieving adequate pain control is often difficult and as a result, quality of life for these patients is poor. Various therapies may be employed in an attempt to provide palliative pain relief including chemotherapy, hormonal therapy, localized radiation, systemic radioisotope therapy, and surgery. Unfortunately, some patients fail to derive satisfactory pain relief with these therapies and relief, when achieved, may not occur until four to twelve weeks after the initiation of the treatment.
Pain management in terminally ill patients with metastases involving bone can be challenging. The conventional therapies may not be viable options for numerous reasons. For example, the limited efficacy or toxic side-effects of chemotherapeutic agents is problematic. Furthermore, localized radiation may not be possible due to radiation resistance of the neoplasms or limitations of further radiation of normal structures. Moreover, the patient may be either a poor surgical candidate or the patient may refuse surgery. When these methods are not possible, or are not effective, analgesic medications remain as the only current alternative therapy for pain relief. Despite these measures, the quality of life for these patients is often poor because of intolerable pain.
There is thus a need for a treatment method effective to palliate pain in patients suffering from bone-tumor associated pain.